interp: Add torepr/0 that converts decode value into what it reptresents

Ex: fq -d msgpack torepr file.msgpack
Willoutput the JSON representation of the msgpack

Make per format *_torepr functions internal

doc/usage.md

@@ -281,6 +281,8 @@ unary uses input and if more than one argument all as arguments ignoring the inp
   - `toactual/0` actual value (decoded etc)
   - `tosym/0` symbolic value (mapped etc)
   - `todescription/0` description of value
+  - `torepr/0` convert decode value into what it reptresents. For example convert msgpack decode value
+  into a value representing its JSON representation.
   - All regexp functions work with buffers as input and pattern argument with these differences
   from the string versions:
     - All offset and length will be in bytes.

format/bencode/bencode.go

@@ -19,6 +19,7 @@ func init() {
 		Description: "BitTorrent bencoding",
 		DecodeFn:    decodeBencode,
 		Files:       bencodeFS,
+		ToRepr:      "_bencode_torepr",
 	})
 }
 

format/bencode/bencode.jq

@@ -1,7 +1,7 @@
-def bencode_torepr:
+def _bencode_torepr:
   def _f:
-    if .type == "string" then .value
-    elif .type == "integer" then .value
+    if .type == "string" then .value | tovalue
+    elif .type == "integer" then .value | tovalue
     elif .type == "list" then .values | map(_f)
     elif .type == "dictionary" then
       ( .pairs

format/bencode/testdata/bbb.fqtest

@@ -275,7 +275,7 @@ $ fq -d bencode v bbb.torrent
 0x3780|62 33 64 2e 72 65 6e 64 65 72 66 61 72 6d 69 6e|b3d.renderfarmin|
 0x3790|67 2e 6e 65 74                                 |g.net           |
 0x3790|               65|                             |     e|         |  end: "e" (valid) 0x3795-0x3795.7 (1)
-$ fq -d bencode bencode_torepr bbb.torrent
+$ fq -d bencode torepr bbb.torrent
 {
   "announce": "udp://tracker.openbittorrent.com:80/announce",
   "announce-list": [

format/bson/bson.go

@@ -21,6 +21,7 @@ func init() {
 		Description: "Binary JSON",
 		DecodeFn:    decodeBSON,
 		Files:       bsonFS,
+		ToRepr:      "_bson_torepr",
 	})
 }
 

format/bson/bson.jq

@@ -1,18 +1,18 @@
-def bson_torepr:
-  def _torepr:
+def _bson_torepr:
+  def _f:
    ( if .type == null or .type == "array" then
       ( .value.elements
-      | map(_torepr)
+      | map(_f)
       )
      elif .type == "document" then
       ( .value.elements
-      | map({key: .name, value: _torepr})
+      | map({key: .name, value: _f})
       | from_entries
       )
      elif .type == "boolean" then .value != 0
-     else .value
+     else .value | tovalue
      end
    );
   ( {type: "document", value: .}
-  | _torepr
+  | _f
   );

format/bson/testdata/test.fqtest

@@ -60,7 +60,7 @@ $ fq -d bson verbose /test.bson
 0x60|                                       6e 75 6c|             nul|      name: "null" 0x6d-0x71.7 (5)
 0x70|6c 00                                          |l.              |
 0x70|      00|                                      |  .|            |  terminator: 0 (valid) 0x72-0x72.7 (1)
-$ fq -d bson bson_torepr /test.bson
+$ fq -d bson torepr /test.bson
 {
   "array": [
     1,

format/msgpack/msgpack.go

@@ -22,6 +22,7 @@ func init() {
 		Description: "MessagePack",
 		DecodeFn:    decodeMsgPack,
 		Files:       msgPackFS,
+		ToRepr:      "_msgpack_torepr",
 	})
 }
 

format/msgpack/msgpack.jq

@@ -1,4 +1,4 @@
-def msgpack_torepr:
+def _msgpack_torepr:
   def _f:
     ( if .type | . == "fixmap" or . == "map16" or . == "map32" then
         ( .pairs
@@ -7,7 +7,7 @@ def msgpack_torepr:
         )
       elif .type | . == "fixarray" or . == "array16" or . == "array32" then .elements | map(_f)
       elif .type | . == "bin8" or . == "bin16" or . == "bin32" then .value | tostring
-      else .value
+      else .value | tovalue
       end
     );
   _f;

format/msgpack/testdata/ints.fqtest

@@ -83,7 +83,7 @@ $ fq -d msgpack v ints.msgpack
 0x20|                                       d2      |             .  |      type: "int32" (0xd2) 0x2d-0x2d.7 (1)
 0x20|                                          80 00|              ..|      value: -2147483647 0x2e-0x31.7 (4)
 0x30|00 01|                                         |..|             |
-$ fq -d msgpack msgpack_torepr ints.msgpack
+$ fq -d msgpack torepr ints.msgpack
 [
   0,
   1,

format/msgpack/testdata/test.fqtest

@@ -84,7 +84,7 @@ $ fq -d msgpack v test.msgpack
 0x40|6c 6c                                          |ll              |
     |                                               |                |      value{}: 0x42-0x42.7 (1)
 0x40|      c0|                                      |  .|            |        type: "nil" (0xc0) 0x42-0x42.7 (1)
-$ fq -d msgpack msgpack_torepr test.msgpack
+$ fq -d msgpack torepr test.msgpack
 {
   "array": [
     1,

pkg/decode/format.go

@@ -19,6 +19,7 @@ type Format struct {
 	RootName     string
 	Dependencies []Dependency
 	Files        fs.ReadDirFS
+	ToRepr       string
 }
 
 func FormatFn(d func(d *D, in interface{}) interface{}) Group {

pkg/interp/decode.go

@@ -75,6 +75,7 @@ func (i *Interp) _registry(c interface{}, a []interface{}) interface{} {
 			"probe_order": f.ProbeOrder,
 			"root_name":   f.RootName,
 			"root_array":  f.RootArray,
+			"to_repr":     f.ToRepr,
 		}
 
 		var dependenciesVs []interface{}

pkg/interp/formats.jq

@@ -1,16 +1,31 @@
 # note this is a "dynamic" include, outputted string will be used as source
 
-( [ ( _registry.groups
-    | to_entries[]
-    # TODO: nicer way to skip "all" which also would override builtin all/*
-    | select(.key != "all")
-    | "def \(.key)($opts): decode(\(.key | tojson); $opts);"
-    , "def \(.key): decode(\(.key | tojson); {});"
-    )
-  , ( _registry.formats[]
-    | select(.files)
-    | .files[]
-    )
-  ]
+def _formats_source:
+  ( [ ( _registry.groups
+      | to_entries[]
+      # TODO: nicer way to skip "all" which also would override builtin all/*
+      | select(.key != "all")
+      | "def \(.key)($opts): decode(\(.key | tojson); $opts);"
+      , "def \(.key): decode(\(.key | tojson); {});"
+      )
+    , ( _registry.formats[]
+      | select(.files)
+      | .files[]
+      )
+    , ( "def torepr:"
+      , "  ( format as $f"
+      , "  | if $f == null then error(\"value is not a format root\") end"
+      , "  | if false then error(\"unreachable\")"
+      , ( _registry.formats[]
+        | select(.to_repr != "")
+        | "    elif $f == \(.name | tojson) then \(.to_repr)"
+        )
+      , "    else error(\"format has no torepr\")"
+      , "    end"
+      , "  );"
+      )
+    ]
   | join("\n")
-)
+  );
+
+_formats_source

pkg/interp/testdata/torepr.fqtest

@@ -0,0 +1,6 @@
+$ fq -i
+null> torepr
+error: value is not a format root
+null> "{}" | json | torepr
+error: format has no torepr
+null> ^D